Recovery and cleaning of condensable gases



Dec. R3, 1949 H. s. ROBINSON 2,491,060

RECOVERY AND CLEANING 0F CONDENSABLE GASES Filed March 12, 1946 2Sheets-Sheet l Ha wa-Yar Dec. 13, 1949 H. s. ROBINSON RECOVERY ANDCLEANING or counn nsaam GASES Filed March 12. 1946 2 Sheets-Sheet 2 aIL'NTOR.

f W C? iforneys JWN amid Dec. 13, m

aacovnnr AND CLEANING or connnnsannn cases Harry S. Robinson, Piqua,Ohio. anignor to The French Oil Mill Ohio Machinery Company, Piqua,

Application March 1:, 1m. Serial No. was:

llclallnl.

This invention relates to the cleaning of condensable gases to berecovered, and more particularly to the removal, cleaning and recoveryof the solvent in a solvent extraction system. In some solventextraction systems, the solids in finely divided form or small particlesare subiected to a soaking treatment with a solvent, during which thesolvent removes from the solids some component of the solids, such asthe fats and oils for example, and at the conclusion of the operation itis desirable to recover and reclaim for reuse, the portion of thesolvent which all of the solvent remaining in or on the solids,

but. agitation of the solids also produces a quantity of relativelyfine-dust, some of which is car- (c ae-izl 2 and a minimum of operatingattention.

- Various other objects and advantages will be Q apparent from thefollowing description of one embodiment of the invention, and the novelfeaadheres to the solids that have been processed.

tures will be particularly pointed out hereinafter in connection withthe appended claims.

In the accompanying drawing:

Fig. 1 is a somewhat diagrammatic elevation of an installationconstructed in accordance with this. invention; and

Fig. 2 is a diagram of part of the drying mechcomplete and eflective isthe extraction operation.

ried off with the current of solvent vapor that I is removed from thepassage, and which must be removed from the solvent vapor before thevapors are condensed, so as to prevent the entrained solids from foulingthe condenser. v

'An object of the invention is to provide an improved method and meansfor removing the solvent remaining in or on the processed solids afterthe excess solvent has been drained oil and cleaning the removed solventto enable its reuse; with which substantially none of the solids treatedwill be lost; which may operate continuously for long periods of timewithout stopping and without clogging of the apparatus; and with whichthe apparatus may be relatively simple, compact, practical andinexpensive.

Another object of the invention is to provide an improved method andmeans for removing dust or finelydividedsolids from solvent vapors topermit-the continuous condensation of such vapors; with which fouling ofthe condenser with dust carried over by the vapors will be prevented;and with which loss of solvent and solids will be relativelyinsignificant.

Another object of the invention is to provide an improved method andmeans for reclaiming the solvent used for solvent extraction operationsand adhering to the solids treated, in a clean condition ready for reuseand with a minimum of low of the solvent; with which the line solidscarried over from the processed material will be recovered and returnedto the processed material; and which will have maximum emciency andeffecm the extraction operation the solids and the solvent aremaintained in prolonged contact with each other to enable the solvent topenetrate the solids and dissolve and carry out a desired component ofthe solids, usually oils and fats, but which may be some othercomponent, such as caifein, which is removed from coflee beans. The Iparticular solvents used and the materials which are treated orextracted are not part of this invention, and hence reference to anyspecific solvents or materials is made only as explanatory of theprinciple of the invention. Usually there is opposed direction ofmovement or flow between the solvent and the solids, sothat the solidsat the endof the extraction treatment are brought into contact withfresh solvent, and any solvent adhering to the solids after thetreatment, will be relatively free of the dissolved-component of thesolids.

At the end of the extraction treatment the solvent and the solids aremechanically separated, such as bydraining oi! the excess solvent, andthen the solids, still wet with some of the solvent,

are moved progressively along a closed passage solids are dried andbegin to go over as a fine I dust with the vapors. The removal of suchsolids or dust from the vapors is important ;in order to prevent foulingof the condenser and to prevent tiveness, and require relatively simpleapparatus loss of the solids so carried over.

Any suitable extraction method or apparatus may be employed, but sincethe manner of ex-- traction is not a part of this invention, it has notbeen illustrated. A part of suitable drying apparatus is illustrated inFig. 2, in which the solids wet with the solvent from the extractiontreatment are delivered through a conduit I, to a dryer mechanismillustrated generally at 2, and which is made up of a plurality ofheated runs or stages arranged one above the other and connected inseries. For example .the feed hopper l opens into one end portion of acylindrical drying shell 3, disposed approximately horizontally andhaving at the end opposite the inlet l a discharge conduit 4 which opensinto one end of another cylindrical shell 5 which extends beneath and isspaced from the shell 3. The shell 5 at its end opposite its connectionto the conduit 4, opens into a conduit 5 leading to another cylindricalshell 1 immediately below, but spaced from the shells 3 and 5. The outerend of the shell 5 is connected by conduit 8 to one end of another shell9 (Fig. 1), similar to shells 3, 5 and I. These shells 3, 5, l and 9 arearranged in a superposed stack and spaced from one another, so that thesolids entering one end of the upper shell 3 may pass along the same tothe opposite end, then into and through the next lower shell, and so ondown through the entire stack until e reach the bottom. v v hile only afew of these shells making up the dryer are shown in Fig. 2, a completestack of them is shown in Fig. 1 in which shells 9, l0, ll, l2 and I3are similarly constructed and disposed below the shells 3, 5, and l. Thedischarge end of the lower dryer shell I3 is connected by a conduit toone end of a screw conveyor l5, by which the processed and dried solidsare conveyed to a suitable point of disposal. Two of such vertical rowsor stacks of cylindrical dryer shells may be employed side by side; andthe discharge conduits H at the bottoms of both stacks deliver driedsolids into a common screw conveyor l5, but such other stack has notbeen illustrated because it and the apparatus attached thereto would bea mere duplication of the apparatus shown in Figs. 1 and 2.

A shaft i6 is disposed endwise and axially in each shell in the stack,such as 3, 5, I and am l3, which shafts extend through the closed endsof the shells where they mount sprocket wheels I! that are connected toeach other by chains I8, and by a chain l9 to an operating motor 20. Themotor 20 operates through a suitable speed reduction mechanism 20a. soas to slowly rotate the shafts It. The shaft It in each shell carries aseries of paddles I60. (see shell 1 in Fig. 2) with bevelled facesresembling propellor paddles or blades of a boat, so that as the shaftrotates, these paddles will act like sections of a spiral screw andpropel the solids along the shell 3 from the inlet conduit l to thedischarge conduit 4. The paddles will, of course, all be similarlyconstructed and bevelled so as to progressively move the solids alongthe shell from end to end and they will, at the same time,

- agitate and stir the loose solids in the shell so as to bring thesolids progressively into contact with the inner periphery of the shellfor heating thereby during their movement along the shell The dryingshell 3 provided with an encircling ia'cket 2| to which steam isadmitted, so that the peripheral wall of the shell will be heated, andthrough contact with this heated 'shell the 4 solids will be heated. Allof the other shells 5, I, and 3 to II, will be similarly heated byjackets 22. In the second shell from the top, which in this example isthe shell 5, there is a vapor outlet pipe 23, preferably locatedintermediate the ends of the shell 5 and opening from the upper partthereof as shown in Fig. l. by which the solvent vapor may be removed.

Similarly all of the other shells 1, 3, l3, ll, l2

and i3 are also provided intermediate of their ends, with outlet pipes24. The shafts "in the shells 5 and I are provided with paddles l5asimilar to those in the shell 3, arranged along the shaft it except fora small section adjacent and passing the outlet 23 where the shaft Itcarries a spiral fin 25 instead of paddles. This short spiral fin 25 onthe shaft acts as a screw conveyor where the solids are passing thevapor outlet opening 23, and there will be less tendency for the solidsto move out through this vapor outlet when the spiral fin is employedthan there would be if the paddles were used for the entire lengths ofthe shell. Paddles and a fin section are similarly provided on each ofthe shafts It in each of the other shells below the shell 5.

The vapor outlet pipes 23 and 24 from the shells 5, l and 9 areconnected to and open into the plenum chamber of a casing 26 which alsohas a vapor outlet into the conduit 21 at the opposite side, or spaced,from the connections to V the pipes 23 and 24. This casing 26 may have atransparent but removable window 23 adjacent its bottom which may beopened in order to pro-' vide access to the plenum chamber for removingany dust that settles out therein. The vapor outlet pipe 21 from casing26 opens into a condenser 29 of any suitable construction. In the typeillustrated, the condenser is provided with heads 30 and 3| connected bya plurality of tubes, so that a cooling water admitted to the head 3|through a pipe 32 may pass through the tubes to the opposite head 30 andthen out through the water outlet 33.

The vapors entering the shell of the condenser will pass around thetubes so as to be cooled thereby and when condensing, by heat exchangewith the water in the tubes, will settle to the bottom from which theymay be removed by a suitable outlet pipe 34 controlled by a valve 35.The upper end of the vapor chamber around the tubes is connected by anoutlet pipe 36 to a second condenser 31 of similar construction, butdisposed at a lower level. The-condenser 31 is cooled by water enteringthe lower header 38 through the water inlet 39, the water passingupwardly from lower head 38 to the upper head 43 through tubes 4|, andthen out through .the water outlet 42.

The vapor outlet of the drying shell I0 is connected by a pipe 43 toanother dust collector having a casing 44, and the pipes 24 of theshells ll, l2 and i3 are similarly connected to the plenum chamber 45 inthis shell 44. These various pipes 24 open into the chamber 45 atdifferent spaced ports, and the casing 44 has a conical bottom 46leading to an outlet pipe 41. This bottom 46 is downwardly convergentand heated by a suitable heating element". Any

suitable heating device 48 may be employed, such as one having steamcoils therein or one having an electric resistance wire incorporatedtherein, or in fact any other suitable means may be provided for heatingthis bottom wall 48.

The upper end of the casing 44 is connected by an elbow49 and a pipe 50to the upper end I of a vapor or gas washer ll. A shaft 62 extendswardly into the plenum chamber 46 from the elbow 49. The shaft 62 iscoupled by a coupling 61 to a shaft 58 of a speed reduction device 69that is supported by a bracket 60 on the elbow 49.

This speed reduction mechanism 69 is operated by a motor iii to which itis coupled. Thus as the motor 66 operates it will slowly rotate theshaft 52. This shaft 62 extends approximately to the level of the upperend of the bottom 46, and carries approximately radial arms 63 which, inturn, are connected at their outer ends to blades 64 that extend alongand in close proximity to the side wall of the casing with extensions 66along and in close proximity to the downwardly convergent bottom 46..The scraper blades 64 i with extensions 65 serve to scrape from thebottom and side walls of the casing, any adherent solids, which collectupon the bottom wall 46.

The washer 5i may be of any suitable construction for washing orscrubbing the solvent vapors to remove any dust entrained therein orcarried in suspension thereby, and in the type illustrated is providedwith a plurality of nozzles 60 arranged in a vertical row along thevertical axis of the washer chamber, and each spraying a liquid as aconical sheet. Thus there will be.

created a superposed group of conical liquid sheets, spaced apartvertically and disposed across the chamber of the washer between theinlet pipe 60 and a vapor outlet pipe 61, which requires the vapors topass through all of these sheets of liquid in order to reach the outlet61. Water or other washing liquid is supplied to the nozzles 66 by apipe 88 leading to a suitable into and remain uncondensedin thecondenser.

Since the condensation oi the vapors will create source, and the liquidsupplied is at a temperature above that at which the vapors willcondense, so that the washing of the vapors with this spray will notcondense any of the vapors but will merely remove the solids suspendedor entrained therein. The liquid from the spray will collect in theconical bottom 69 having an outlet pipe HI controlled by'a valve H.

The vapor outlet 61 from the washer opens into the chamber of condenser31 that surrounds the vertically extending tubes 4|, and the cleanedvapors are condensed and collect in the bottom of the shell of thecondenser 3T from which they are removed by a pipe I2 controlled by avalve 13 leading to a storage tank for the solvent. The pipe 36 from theupper condenser 29 opens into the upper part of the vapor chamber of thecondenser 31, so that if any vapors pass the upper condenser in vaporform, they will be condensed in the condenser 31. The condensation ofthe solvent vapors in the chambers of condensers 28 and 31 will producea partial vacuum or suction which will be communicated through thewasher 5|, the dust collectors 26 and 45, to the various stretches orruns of the passage through which the solids are being progressivelymoved during the drying.

The vapor chamber of the condenser 21' is provided with a vent pipe 14controlled by a valve 16 which leads to a carbon adsorber I6 which, inturn, is connected by a pipe 11 to a device 18, such as a pump orbarometric condenser, which creates a suction in the vapor chamber ofthe condenser and removes any air or uncondensed a suction, it is onlynecessary to operate the suction device 18 at lntervals,such as whenstarting, or when the condenser contains a substantial quantity of airor uncondensible vapor. The carbon adsorber serves to remove any of thesolvent vapor that might be carried over during the short intervals inwhich the suction device it is operating.

It is desirable that none oi the solids subjected to the extractionprocess be lost, .and therefore the sludge formed of the solids andliquid, such as water, collecting in the bottom as of the washer will beconveyed by the-pipe 1a to a conveyor 19 which discharges into thelarger conveyor i6 that receives the solids discharged from the dryershell i3. Similarly the outlet 41 at the bottom of the casing 44 opensinto a screw conveyor 80 of the lock seal type which has 'a spiral screw85 therein that slowly removes the dust from the bottom of the plenumchamber 45 and delivers it into a pipe 82 while sealing opening 41. Thedischarge pipe 82,is also connected to the conveyor 19 so that thesolids removed from the plenum chamber 45 will also be returned to thedry solids discharged through the conduit i4 into the conveyor i5. Itwill be observed that with such connections all of the solids comingfrom the solvent extraction operation will be delivered at the dischargeend of the apparatus, and substantially all of the solvent will beremoved, cleaned and recovered to enable its reuse alter the componentthat was dissolved in the solvent has been separated from the solvent.

In the operation oi this improved apparatus,

the solvent remaining in and on the-solids iollowwith the adherentsolvent are heated in this manner above the vaporizing temperature ofthe solvent, and thus all of the solvent on the surface of the solidswill be vaporized and removed through the outlet pipes 23 and 24, andthe solvent in the interior of the solids will also be vaporized andremoved in a similar way.

Little or no solvent vapor is formed in the upper dryer shell 3, becauseduring the travel of the solids in that shell the solids and solvent arebeing brought up to the vaporization temperature for the solvent. Thevapors passing off from the shells 5, I and 9 carry little or no dustwith them because the solids are still quite wet with the solvent, whichlays any dust in the solids, but

whatever solids are carried on from those shells will be largely settledout in the plenum chamber of casing 26. When solids have collected inthe casing 26 to any substantial extent, they may through pipe 36 to thelower condenser 31 where they are fully condensed, if they arecondensible, and those that are not condensible may be removed atintervals through the pipe 14. The

vapors from the drying shells II, H, I! and I! are removed through thecollector 44 having a plenum chamber 45, and the larger particles of thedust carried over by these vapors will settle out in chamber 45, and thevapors with the remaining or lighter solid or dustparticles will move oninto the gas washer The dust of the solids being processed will becarried oil largely by the vapors leaving the shells III to l3, becauseat this stage in the processing of the solids, the solids are becomingdryer, and when the dust is dry it will, through the agitation of thesolids, pass off to some extent with the vapors. The scraper 64, 65prevents a building up on the side walls and bottom of chamber 5 of thedust particles separated out in the chamber 45. The solids collected onthe bottom 45 will be heated by the heater 48, so that any solventadhering to such solids will be vaporized and will pass of! with theother vapors into the washer ii In the washer 5| there is norecirculation of the washing liquid, and water is the usual liquidemployed for the washing or scrubbing of the gas or vapors. temperatureabove the condensation temperature of the solvent vapors, and thereforethe solids are sages, one of said passages being connected to the outletof said washer, and the other passage being connected to a source ofcooling fluid, said casing having a downwardly convergent bottom belowsaid ports for collecting dust particles settling out in said chamber,with a discharge opening in said bottom for the removal of the settledout dust particles, and a source of heat,

- sively, a closed casing connected to said means This water or liquid,of course, is'at a 1 washed out without condensation of the vapors.

The sludge formed of the water and washed out solids will collect inthebottom 6! of the washer,-

and willpass therefrom throughthe valve II and pipe II into the conveyor18 which delivers the sludge to the dried solids discharged from thelower dryingsheil, is. bottom of the chamber, are also removed throughthe conveyorseai 8i, and are similarly delivered to the processedsolids. Thus substantially all of the solids treated will be dischargedby the conveyor [5, and the mixture of the sludge from the washer withthe driedsolids restores humidit to the solids-in the conveyor l5sufilciently to facilitate handling of the solids, and the working ofthem into suitable shapes when the solids are pressed into cakes.

For example if the solids are to be used for stock feed, a-littlemoisture mixed therewith aids in forming the processed solids into cakesand does no harm. All of the solids carried over by the vapor will beremoved before reaching the condenser, and thus will not foul thecondenser. With such an arrangement, the apparatus may operatecontinuously for relatively long intervals of time without shutting downfor cleaning of the condenser or other parts. By using fresh watercontinuously in the washer 5|, there will be no fouling or plugging ofthe spray nozzles.

It will be understood that various changes in the details, materials andarrangements of parts, which have been herein described and illustratedin order to explain the nature of the invention, may be made by thoseskilled in the art within the principle and scope of the invention, asexpressed in the appended claims.

I claim:

1. In a system for cleaning condensable gases to be recovered, a closedcasing having a plenum chamber of substantial size and spaced inlet andoutlet ports opening therein both above its 'bottom, 2. source of dustladen condensable'gases connected to the inlet port of said chamber, agas washer connected to the outlet port of said chamber to wash thegases with a liquid which will not absorb the gases. a condenserconnected to said washer to remove and condense washed gas therefrom,separately from the wash liquid and having entirely separate heatexchange pas- The solids from the said washer.

for progressively receiving therefrom the vaporized solvent withentrained solids, and having a plenum chamber of substantial size inwhich some of the solids may settle out from the vapors, a gas washerconnected to said casing to receive said vapors with remaining entrainedsolids, and

for washing out said remaining solids with a liquid at a temperatureabove that at which said solvent vapors will condense, 'a condenserconnected to said washer for removing and condensing said washed vaporsfrom said washer, and means for delivering to the discharged, driedsolids, the solids removed in said casing and in 3. In amethod forremoving a condensable solvent,to be recovered, from a finely dividedmass of solids discharged from a solvent extraction treatment, theimproved steps which comprise passing the solvent carrying solids alonga closed passage andagitating the solids during movement along suchpassage, heating the solids during such movement to vaporize the solventadhering to said solids, removingithe vapors from said passage,mechanically separating out the heavier entrained solids passing oilwith said vapors, washing the resultant vapors having any remainingsolids suspended therein with fresh liquid free of said solids, at atemperature above .that at which said solvent vapors will condense,

collecting and condensing the washed vapors, and adding the wash waterwith its suspended solids, and the mechanically separated solids, to thedried solids delivered by said passage and from which the vapors wereremoved.

4. In a method for removing a condensable solvent, to be recovered, froma finely divided mass of solids discharged from a solvent extrac-' tiontreatment, the improved steps which comprise passing the solventcarrying solids along a closed passage and agitating the solids duringmovement along such passage, heating the solids during such movement tovaporize the solvent adhering to said solids, removing the vapors fromsaid passage, mechanically separating out the heavier entrained solidspassing off with said vapors, heating the mechanically separated solidsto eliminate therefrom any solvent remaining thereon. and addingsuch'vapors to those which are subjected to washing, washing theresultant vapors having any remaining solids suspended therein withfresh liquid free of said solids, at a temperature above that at whichsaid solvent vapors will condense, collecting and condensing the washedvapors, and adding the wash water with its suspended solids, and themechanically 7 separated solids, to the dried solids delivered by washerconnected I 9. said passage and from which the vapors were removed.

5. A'system for treating solids from a solvent agitated while inmovement, a vapor washer, a

extraction operation to remove and recover the solvent, which comprisesa closed passage along which the solvent carrying solids from saidextraction treatment are passed-and in which the solids are agitatedduring such-v passage, means for heating the solids whilein said passageto vaporize the solvent carried thereby, a dust collector connected tosaid passage for removing therefrom the vaporized solvent with any dustfrom said solids entrained therein, a washer connected to said dustcollector for receiving the vapors from said collector with remainingsolids suspended therein and washing the'vapors with a liquid at atemperature above the condensation temperature of said vapors, acondenser connected to said washer for removing the washed vapors andcondensing and'collecting them, a connection from the Washer to saidpassage for delivering the washer liquid and solids collected thereby tosaid passage at a zone following that at which the vapors were removed,and a connection from said collector to said passage for also deliveringback into the passage the solids separated out in said collector;

6. A system for treating solids from a solvent extraction operation toremove and recover the solvent, which comprises a closed passage alongwhich the solvent carrying solids from said extraction treatment arepassed and in which the solids are agitated during such passage, meansfor heating the solids while in said passage to vaporize the solventcarried thereby, a dust collector connected to said passage for removingtherefrom the vaporized solvent with any dust from said solids entrainedtherein, and operable to remove some of the entrained solids, a washerfor receiving the vapors from said collector with remaining solidssuspended therein and washing the vapors with a liquid at a temperatureabove the condensation temperature of said vapors, a condenser connectedto said washer for removing the washed vapors and condensing andcollecting them, a connection from the washer to said passage fordelivering the washer liquid and solids collected thereby to saidpassage at a zone thereof following that at which the vapors wereremoved, and a connection from said collector to said passage for alsodelivering back into the passage the solids separated out in saidcollector, said collector having its lower part heated to preventcondensation of vapors on the separated out solids.

7. In a system for cleaning condensable gases to be recovered, a closedcasing having a plenum chamber of substantial size and spaced portsopening therein, a source of dust laden condensable gases connected toone of said ports, a gas to another port of said chamber, a condenserconnected to said washer for receiving therefrom and condensing thewashed gases, a source of fresh, clean washing liquid connected directly,to said washer for delivering said liquid directly thereto, and aconnection for receiving and mixing the liquid from said washer and dustseparated from the gas in said plenum chamber.

8. A system for removing a condensable solvent, to be recovered, from afinely divided mass of solids which are wet with said solvent, and torcleaning said solvent, which comprises a closed passage through whichthe solids wet with said solvent may be moved progressively andconnection from said washerto said passage for removing dust ladenvapors from said passage and conveying them to said washer, a condenserconnected to said washer for removing therefrom and condensingsaidsolvent vapors, a source of fresh, cleaning w'ashing liquid at atemperature above the condensing temperature of said-solvent connectedto said washer, said washer having spray means connected to said liquidsource for spraying said fresh liquid across the path of movement of thegases through said washer so as to wash out suspended solids, and meansfor collecting the used wash liquid with entrained solids and deliveringthem back to said passage in a portion thereof following that in whichthere was removal of vapors.

9. A system for treating solids from a solvent extraction operation toremove and recover the solvent, which comprises a closed passage alongwhich the solvent carrying solids from said extraction treatment arepassed and in which the solids are agitated during such passage, meansfor heating the solids while in said passage to vaporize the solventcarried thereby, a pair of mechanical dust separators, one connected toreceive vapor from said passage in the first half of the solids travelthrough said passage, and the other connected to receive vapor from aplurality of portions of said passage further along in the travel ofsolids therethrough, a pair of condensers each of the type havingseparate vapor and cooling heat exchange chambers, one of saidcondensers having its vapor chamber connected to receive vapors leavingsaid one sep-- arator and discharge any non-condensed vapors into thevapor chamber of the other condenser,

'a washer connected to receive vapors from the other of said separatorsand deliver them to said vapor chamber of said other condenser, meansfor passing a cooling fluid through the cooling chambers of saidcondensers, means for spraying.

a washing liquid across the stream of, vapors in said washer to wash outentrained solids, and means for creating a partial vacuumin the vaporchamber of said other condenser and removin uncondensed gases therefrom.

10. A system for treating solids from a solvent extraction operation toremove and recover the solvent, which comprises a closed passage alongwhich the solvent carrying solids from said extraction treatment arepassed and in which the solids are agitated during such passage, meansfor heating the solids while in said passage to vaporize the solventcarried thereby, a pair of mechanical dust separators, one connected toreceive vapor from said passage in the first half of the solids travelthrough said passa e and the other connected to receive vapor from aplurality of portions of said passage further along in the travelofsolids therethrough, a pair of ;.condensers each of the type havingseparate 'vapor and cooling heat exchange chambers, one

of said condensers having its vapor chamber connected to receive vaporsleaving said one separator and discharge any non-condensed vapors intothe vapor chamber of the other condenser, a washer connected to receivevapors from the other of said separators and deliver them to said vaporchamber of said other condenser, means for passing a cooling fluidthrough the cooling chambers of said condensers, means for spraying awashing liquid across the stream of vapors in said washer to wash outentrained solids, means for creating a partial vacuum in the vapor 11chamber or said other condenser and removing uncondensed gasestherefrom, and means for conducting the solids collected in said other8CD? arator and the spra liquid and solids entrained therein from saidwasher, to the body of solids leaving said passage.

11. A method of recovering a condensible solvent from a mass of solidswet thereby, which comprises agitating and heating said wet solids in aconfined space to vaporize the solvent adhering to the solids, removingthe solvent vapors from said space, mechanically separating and heatingheavier entrained solids from the separated vapors, then washing theresultant vapors with an entirely fresh liquid free of solids at atemperature above that at which the solvent vapors will condense andwhich will not absorb the vapors, collecting and removing the washedvapors to free them of the wash liquid, adding the wash liquid andentrained solids to the first solvent-freed solids, and then condensingand recovering the washed vapors free 0! said wash liquid and anyentrained solids.

HARRY s. ROBINSON.

12 summons mm The following references are of record in the file of thispatent:

UNITED STATES PATENTS Number Name Date 327,948 Johnstone Oct. 6, 1885470,608 Wardhaugh Mar. 8, 1892 962,118 Bradley June 21, 1910 1,145,903Lehrack et al. July 13, 1915 1,151,417 Stokes Aug. 24, 1915 1,165,401Fender Dec. 28, 1915 1,297,639 Blumenberg, Jr. Mar. 18, 1919 1,927,313Hagen et a1 Sept. 19, 1933 1,940,199 Wagner Dec. 19, 1933 2,098,024Bailey Nov. 2, 1937 2,321,893 Bimpson June 15, 1943 2,334,015 Levine etal Nov. 9, 1943

